Double apron drafting system for drawing frames



G. ANDREANI Feb. 14, 1967 DOUBLE APRON DRAFTING SYSTEM FOR DRAWING FRAMES 6 Sheets-Sheet 1 Filed July 28, 1964 Feb. 14, 1967 G. ANDREANI4 DOUBLE APRON DRAFTING SYSTEM FOR DRAWING FRAMES 6 Sheets-Sheet 2 Filed July 28, 1964 INVENTOR. GIANFRANCO ANDREAN\ B +7f uuwL ATTORNEY 5 G. ANDREANI 3,303,534

DOUBLE APRON DRAFTING SYSTEM FOR DRAWING FRAMES 7 Feb. 14, 1967 6 Sheets-Sheet 3 Filed July 28, 1964 m m M mm mm m EJ F N1 i Q9 8 2 Q Q. m wmwv Q} f Q N m F H N5 l9 J on, om- Q 9 Q 3 El? E mm ATTORNEYS G. ANDREANI 3,303,534

DOUBLE APRON DRAFTING SYSTEM FOR DRAWING FRAMES Feb. 14, 1967 6 Shets-Sheet 4 Filed July 28, 1964 G. ANDREANI 3,303,534 DOUBLE APRON DRAFTING SYSTEM FOR DRAWING FRAMES Feb. 14, 1967 6 Sheets-Sheet 5 Filed July 28, 1964 W H mi 5 .5 m Q1 fi .5 .8 V k W l\ mm. m N9 u Feb. 14, 1967 G. ANDREANI 3,303,534

DOUBLE APRON DRAFTING SYSTEM FOR DRAWING FRAMES Filed July 28, 1964 6 Sheets-Sheet 6 United States Patent 3,303,534 DOUBLE APRON DRAFTING SYSTEM FOR DRAWING FRAMES Gianfranco Andreanl, S. 0. M. Andreani & 0., Via F. Corridoni 31, Bergamo, Italy Filed July as, 1964, Ser. No. 385,689 Claims priority, application Italy, Aug. 21, 1963, 17,335/63; Nov. 28, 1963, 24,578/63; Dec. 11, 1963, 25,232/63; Jan. 15, 1964, 843/64 19 Claims. (Cl. 19-248) This invention relates to an improved double apron drafting system particularly devised to straighten and parallelize textile fibers while drafting the same on drawing frames.

Various arrangements of double aprons have served quite well in the drafting of small or condensed, previously parallelized, fibrous strands or individual strands as they are processed on roving frames and spinning frames. However, textile slivers, as they are drafted on drawing frames, especially as the slivers come from carding machines, are in the form of loose masses of fibers which are largely randomly oriented, some of the fibers tend to cling or adhere to each other to a greater extent than others, and the shorter fibers are not evenly distributed along the lengths of the slivers. It is necessary, therefore, in the drafting of textile slivers on drawing frames, to so control the fibers that they may be parallelized by relatively gliding over each other without the individual fibers becoming bent upon themselves or coiled up and forming undesirable wads therefrom or destroying the parallelization thereof. To my knowledge, the use of prior art types of double apron drafting systems on drawing frames has not been successful due to failure of the same in controlling the fibers effectively in their course between the double aprons.

It is therefore an object of this invention to provide a novel double apron drafting system for doubling a number of slivers of natural artificial and/or synthetic fibers while effectively controlling the fibers in their course between the drafting aprons by permitting the fibers to relatively glide over each other, and preventing-them from coiling upon themselves, to thereby distribute and impart a high degree of parallelization to the fibers to an extent heretofore unattainable, even though the drawing frame may be operating at very high speed.

It is another object of this invention to provide an adjustable double apron drafting system capable of processing fibers of from about inch up to 4 /2 inches staple length and more. To my knowledge, prior art fixed apron systems have been capable of processing fibers of from about 1%; inches up to 3%; inches staple length only.

It is still another object of this invention to provide a double apron drafting system including top and bottom endless aprons positioned between and spaced from front and rear pairs of drafting rolls with means for applying a predetermined high yieldable downward pressure to a supporting roller for the rear portion of the top apron and other means for applying a predetermined relatively low yieldably downward pressure to the means for supporting the front portion of the top apron substantially independently of the means for applying pressure to the rear top-apron-suporting roller.

Another object of this invention is to provide a pair of upper and lower superposed control rollers between which the proximal runs of the top and bottom aprons are adapted to move in engagement therewith, with means supporting one of the control rollers in a fixed position and means applying a predetermined yieldable pressure to the other of the control rollers toward said one control roller, the control rollers being arranged to operate substantially independently of the means for supporting the corresponding aprons.

Still another object of this invention is to provide means for adjusting the control rollers toward and away from the front or delivery drafting rolls and relative to the corresponding apron-supporting meansin accordance with the length of the fibers being processed. I

Another object of this invention is to provide means for removing slack from and maintaining taut each of the aprons.

It is a more specific object of this invention to provide a double apron drafting system including top and bottom endless aprons or belts, with rollers supporting the same and wherein the aprons are located between sets of feed rolls and delivery rolls. The top-apron-supporting rollers are mounted in a pair of spaced end blocksor plates forming a cradle pivotally mounted on or adjacent the rear top-apron-supporting roller with means applying a predetermined yieldable downward pressure to the cradle adjacent and forwardly of the latter roller.

. Means also are provided for applying a predetermined yieldable pressure to the latter roller. Thus, in addition to a predetermined pressure being applied at the rear portions of the aprons, pressure is applied to the cradle, which pressure is of gradually diminishing magnitude from v the rear to the front portions of the aprons to permit relative movement of short and long fibers therebetween as they are drafted.

Control of the fibers is further improved by means of the upper and lower control rollers engaging predetermined medial portions of the proximal runs of the respective top and bottom aprons and positioned according to the length of shorter fibers in the slivers, with means applying a predetermined downward pressure to the top control roller independently of the pressure ap plied to the cradle and the rear apron-supporting roller.

Some of the objects of the invention having been stated,

other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which:

FIGURE 1 is a top plan view of the drafting instrumentalities of a drawing frame embodying my improve-zldouble apron drafting system, with portions of the pressure applying mechanisms being broken away and shown in cross-section in the right-hand portion thereof;

FIGURE 2 is a partial elevation and partial vertical sectional view looking rearwardly substantially along line FIGURE 5 is a partially exploded perspective view of the top and bottom aprons and corresponding cradles removed from the drawing frame;

FIGURE 6 is a fragmentary vertical sectional view taken substantially along line 6-6 in FIGURE 4;

FIGURE 7 is an enlarged fragmentary vertical sectional view taken substantially along line 7 7 in FIGURE 2 and showing the pressure applying means more in detail;

FIGURE 8 is a vertical sectional view taken transversely of the drafting rolls and corresponding substan tially to FIGURE 4, with parts broken away to illustrate a modified form of means for adjusting the displacement between the front drafting rolls and the double aprons and between the double aprons and the back drafting rolls; and

FIGURE 9 is a fragmentary vertical sectional view, mostly in elevation, taken substantially along line 9-9 in FIGURE 8.

Referring more specifically to the drawings, the numeral 10 indicates the main girt or frame of the drawing frame to which a pair of forwardly and rearwardly extending and laterally spaced elongate roll stands 11, 11 are suitably secured. Roll stands 11, 11' are providedwith respective longitudinally extending key portions 12, 12' on the upper surfaces thereof for supporting and guiding respective sets of bearing blocks 13, 14,15 and 13, 14', 15' thereon.

A bottom feed roll or back drafting roll 16 is journaled in and extends between bearing blocks 13, 13'; a bottom delivery or front drafting roll 17 is journaled in and extends between bearing blocks 15, 15; and a rear bottomapron-supporting roll or roller 18 is journaled in and extends between bearing blocks 14,-14'. Rolls 16, 17, 13 may be driven in a well-known manner, such as by means of a motor 21 and intervening connections 22 which are shown schematically in FIGURE 1. As is usual, bottom drafting roll 16 is driven at a given speed and the rolls 17, 18 are driven at progressively increasing speeds in accordance with the amount of draftto be imparted to slivers S being fed from a suitable source, not shown, over the back bottom feed roll 16.

The roll stands 11, 11' are provided with respective longitudinally extending adjustment slots 23 therein loosely penetrated by respective bolts 24, 24', 25' for adjustably securing respective bearing blocks 13, 14; 13', 14 to, roll stands 11,11. Bolts 24, 25, 24', 25 have corresponding T-nuts T threaded on the lower ends thereof (FIGURES 3 and 1).

A top feed roll or rear top drafting roll 16a and a top delivery roll or front top drafting roll 17a are positioned above the respective rolls 16, 17 and reduced opposite ends thereof are journaled in respective pairs of elongate bearings 26, 26', 27, 27' which preferably are circular in cross-section and whose closed distal ends have respective reduced portions or projections 30, 30, 31, 31 integral therewith. Reducedportions 3t 30 ofbearings' 26, 26' fit in grooves 32, 32' formed in the upper portions of the respective rear or back bearing blocks 13, 13. Reduced portions 31, 31 of bearings 27, 27 also fit in corresponding grooves 33, 33' formed in the proximal faces of'respective bearing blocks 34, 34 adjustably mounted on the upper ends of bearing blocks 15, 15.

Bearing blocks 15, 15- are suitably secured to roll stands 11,11 by respective screws 35, 35' which also extend through respective upwardly projecting portions 36, 36' on the front ends of bearing blocks 15, 15'.

Adjustment screws 37, 37' loosely penetrate rising projections36, 36' on the respective bearing blocks 15, 15 and are threaded .into the bearing blocks34, 34'. The front ends-of screws 37, 37 may have respective knurled heads 38, 38' thereon. It is apparent that turning of the screws 37, 37' adjusts bearing blocks 34, 34 and top delivery roll 17a forwardly and rearwardly relative to roll stands 15, 15 and bottom delivery roll 17.

A novel double apron drafting arrangement between feed rolls 16, 16a and delivery rolls 17, 17a comprises wide top and bottom endless belts or aprons 40, 41 made from synthetic or natural rubber or other strong pliable material and which are mounted on respective top and bottom carriages or cradles, broadly designated at 42, 43. Bottom apron 41 is entrained about the driven rear bottom-apron-supporting roller 18, a front relatively small bottom-apron-supporting member or roller 44 and a primary bottom-apron-tensioning roller 45 so the bottom apron 41 is formed with a top run which extends substantially horizontallyand is disposed on a plane substantially corresponding to' the nips of drafting rolls 16, 16a

- and 17, 17a.

A substantial portion of the top run of bottom apron 45 is supported throughout its width on a stationary shoe 46 whose upper surface may be curved substantially as shown in FIGURE 4 and whose rear edge terminates in close proximity to rear bottom-apron-supporting roller 18. Shoe 46 is a part of carriage 43 and opposed ends thereof are provided with rectangular extensions 46a, 46a suitably secured to the front surfaces of the respective bearing blocks 14, 14 (FIGURES 1, 3, 4 and 5).

Bottom cradle 43 also comprises a pair of laterally spaced end plates or blocks 50, 50' suitably secured to end extensions 46, 46a of shoe 46 and projecting forwardly therefrom. The front ends of end blocks 50, 50' straddle the bottom apron 41 and have reduced opposite ends of the front bottom-apron-supporting roller 44 journaled therein as shown in FIGURE 6.

In order to take up any slack in bottom apron 41 and to maintain the same taut while permitting freedom of movement of apron 41, opposed ends of the primary tensioning roller 45 are journaled on flanged stub stafts 45a, 45a whose distal portions are mounted .in respective tension adjusting disks or blocks 53, 53' (FIGURE 2). Tension adjusting disks 53, 53' are of cup-like or hollow construction and are journaled for angular adjustment on the circular proximal ends of bearing brackets 54, 54. Bearing brackets 54, 54 extend upwardly and outwardly and are suitably secured to the respective bearing blocks 14, 14' (FIGURES 2 and 3).

It should be noted that primary apron-tensioning roller 45 is positioned in eccentric relation to the axis of disks 53, 53. A secondary apron-tensioning roller 55 is positioned to engage the outer surface of apron 41 at a point between rear bottom-apron-supporting roller 18 and primary apron-tensioning roller 45; i.e., secondary tensioning roller 55 extends substantially parallel with roller 45 and is positioned in substantially diametrically opposed relation thereto with respect to disks 53, 53'.

Roller 55 is journaled also on a pair of flanged stub shafts 55a, 55a whose distal ends are suitably secured to disks 53, 53. Disks 53, 53' may be rigidly interconnected by a bridging bar 56 (FIGURE 4). Disk 53 has a substantially radially extending handle bar 57 fixed thereto and projecting forwardly therefrom so that it may readily be grasped by an operator for imparting angular movement to disks 53, 53 to adjust the tension in bottom apron 41.

Disks 53, 53 may be locked in the desired adjusted position by means of a set screw 59 which extends'through the outer annular portion of disk 53 and bears against the circular hub portion of the corresponding bearing bracket 54 (FIGURES 2 and 3). The distance between the flanges of stub shafts 45a, 45a and stub shafts 55a, 55a should be substantially the same as or slightly greater than the width of bottom apron 41 so as to assist in guiding the same during movement thereof in engagement with tensioning rollers 45, 55.

Top cradle 42 comprises a pair of end plates or block 60, 69, each of which preferably is shaped substantially according to the contour of the outer surface of top apron 40. End blocks 60, 60' are spaced apart a distance substantially equal to or slightly greater than the width of topapron 4i) and bear against shoulders formed by reduced opposite ends of a rod 61 which ends penetrate and are secured to end blocks 60, 60 by threaded pivot pins or pressure receiving pins 62, 62' for top cradle 42 (FIGURE 5).

Rear and front portions of top apron 40 are supported by respective rear and front top-apron-supporting rollers 64, disposed above the respective bottom-apron-supporting rollers 18, 44 so as to form a bottom run of the top apron 40 extending substantially parallel with and in close proximity to or in engagement with the top run of bottom apron 41. Reduced opposite ends of rear topapron-supporting roller 64 loosely penetrate the rear portions of end blocks 60, 60' of cradle 42' and have respective elongate bearings 67, 67' mounted thereon, which bearings may be suitably attached to the distal surfaces of end blocks 60, The distal ends of bearings 67, 67 have respective reduced portions or axial projections 70, 70 thereon which loosely fit in grooves 71, 71 (FIGURE 1) formed in the upper portions of respective bearing blocks 14, 14. Thus, cradle 42 is, in effect, pivotally mounted on roller 64.

Reduced opposite ends of front iop-apron-supporting roller 65 may be journaled in end blocks 60, 60' in the same manner in which the ends of front bottom-apronsupporting roller 44 are journaled in end blocks 50, 50', as shown in FIGURE 6.

As best shown in FIGURES 2 and 4, the upper portion of top apron 40 is entrained over a tensioning roller 75 whose length is substantially the same as the width of top apron 40 and opposed ends of which are journaled on a pair of stub shafts 75a, 75a (FIGURES 1, 2 and 4). Stub shafts 75a, 75a are loosely positioned in substantially vertically extending slots or cavities 76, 76' (FIGURES 4 and 2, respectively) formed in the respective end blocks 60, 60 of top-cradle 42.

The upper portions of end blocks 60, 60' are loosely penetrated by respective adjustment screws 77, 77' (FIG- URE 1) which extend into the corresponding slots 76, 76' and are threaded through the corresponding stub shafts 75a, 75a. It is apparent that, by turning screws 77, 77 in one direction, top-apron-tensioning roller 75 may be moved upwardly relative to end blocks 60, 60' to increase the tension in top apron 40.

Means are provided for applying predetermined relatively high yieldable downward pressure to the top drafting rolls 16a, 17a and the rear top-apron-supporting roller 64, and for applying predetermined relatively low pressure to the pins 62, 62' (FIGURE 5) of cradle 42, as will be later described. Since cradle 42 is pivotally supported by rear top-apron-supporting roller 64, it is apparent that the slivers S are initially subjected to a high pressure as they enter between the double aprons 40, 41 and are then subjected to gradually diminishing pressure by aprons 40, 41 as they are advanced toward the front end of the proximal runs thereof and are drafted by the delivery rolls 17, 170. This feature, coupled with the fact that bottom apron 41 is a driving apron and the top apron 40 is driven only by engagement thereof with the bottom apron and/or the slivers S passing between the aprons, insures that the fibers are gripped firmly between the rear portions of the proximal runs of aprons 40, 41 as the fibers forwardly of the rear apron-supporting rollers 18, 64 are released from the gripping action to a certain extent so as to permit them to glide relative to each other,

thereby assisting in straightening and parallelizing the fibers as they are drafted along the aprons 40, 41 and between the aprons and delivery rolls 17, 17a.

Since fibrous masses generally include fibers of various lengths and it frequently happens that short fibers of as little or less than inch in length are present in slivers which may include long fibers of 4 /2 inches or more in length, I have found that control of the fibers generally and attenuation and distribution of the shorter fibers are improved by applying a localized zone of pressure along a transverse line throughout the width of the aprons at a predetermined point spaced rearwardly from the nip of the delivery rolls 17, 17a and intermediate the ends of the proximal runs of aprons 40, 41. Accordingly, I have provided a pair of superposed relatively small lower and upper fiber control rollers 82, 83 which extend substantially throughout the width of the respective aprons 40, 41 and engage the lower and upper surfaces of the respective bottom and top runs of aprons 40, 41.

Opposite ends of lower control roller 82 loosely extend through forwardly and rearwardly extending notches or slots 84, 84' in end blocks 50, 5t) (FIGURES 4, 5 and 7) of bottom cradle 43. Reduced opposite endsof lower control roller 82 are journaled in respective elongate bearings 85, 85 which preferably are circular in cross-section and whose proximal ends are spaced outwardly from the main body of control roller 82. Bearings 85, 85 rest upon supporting surfaces 86, 86' (FIGURES 3 and 5) of end blocks 50, 50'. Thus, control roller 82 is rotatably supported by end blocks 50, 50' of bottom cradle 43.

Reduced opposite ends of upper control roller 83 loosely extend through elongate forwardly and rearwardly extending slots 90, 911' in end blocks 60, 60' and are journaled in respective elongate bearings 91, 91 which preferably are circular in cross-section and whose distal ends are provided with reduced portions or projections 92, 92 adapted to fit loosely in vertically extending slots or grooves 93, 93' formed in respective bearing blocks 94, 94' (FIGURE 1). Bearing blocks 94, 94 are adjustably secured to the respective roll stands 11, 11' by corresponding screws 95 (FIGURE 1) and nuts 96 (FIG- URES 2 and 3) in the same manner as that described for the bearing blocks 13, 14, 13, 14'.

As best shown in FIGURES l and 2, the bearing blocks 94, 94' are provided with respective inwardly projecting lower portions 160, 100 whose upper surfaces are spaced below bearings 91, 91 and have respective vertically extending slots 101, 101 therein for receiving therein relatively small reduced portions or axial projections 102, 102 on the distal ends of bearings 85, 85 for lower control roller 82. It is thus seen that, by loosening screws 95, bearing blocks 94, 94 may be adjusted longitudinally of roll stands 11, 11' to adjust control rollers 82, 83 forwardly and rearwardly, in unison, relative to the apronsupporting cradles 42, 43 and delivery rolls 17, 17a in accordance with the length of the shorter fibers in the slivers S. The optimum position of control rollers 82, 83 with respect todelivery rolls 17, 170 may thus be determined empirically. Generally, the distance between the nips of control rollers 82, 83 and drafting rolls 17, 170 should be about equal to one-half the difference between the longest and shortest fibers being processed.

It should be noted that the vertical height of slots 90, 90' (FIGURES 4 and 5) in end blocks 60, 60 is sufficient to permit variation in the distance between control rollers 82, 83 in accordance with variations in the density and thickness of slivers S passing between aprons 40, 41 and so that yieldable downward pressure applied to the upper control roller 83 is effective in applying yieldable squeezing pressure to the corresponding portions of the aprons 40, 41 and the slivers S passing therebetween.

The means for applying predetermined yieldable downward pressure to top drafting rolls 16a, 17a, rear top apron-supporting roller 64, top cradle 42 and upper control roller 83 will now be described. Two composite pressure applying devices 110, are provided adjacent opposite sides of cradle 42, as best shown in FIGURES 1 and 2, both of which are constructed of similar parts which will bear the same reference numerals, where applicable, wtih the prime notation being applied to those reference numerals applied to the parts associated with composite pressure applying device 110'.

As shown in FIGURES 3 and 7, the composite pressure applying devices 110, 110 include respective series of spring-loaded plungers 113117 and 113'-117. The lower ends of plungers 113, 114, 116, 117, 113, 114', 116', 117 bear against the upper surfaces of the respective bearings 26, 67, 91, 27, 26, 67, 91, 27' and the lower ends of plungers 115, bear against the respective pivot pins 62, 62'.

Each plunger 113-117 loosely penetrates the restricted lower end of a corresponding tubular housing 120 and each plunger 113117 loosely penetrates the restricted lower end of a corresponding tubular housing 120. Each housing 120 associated with plungers 113, 116, 117 loosely penetrates a pair of vertically spaced collars or guide blocks 121, 122 which extend between and are guided for adjustment longitudinally of a pair of cloosely spaced parallel lever arms 124. Lever arms 124 extend rear- 7 wardly of feed rolls 16, 16a and are pivotally connected, as at 125, to a corresponding post 126 suitably secured to roll stand 11.

Since the distance between plungers 114, 115 of FIG- URE 3 remains constant at all times, both housings 120 corresponding thereto are mounted in and loosely penetrate lower and upper guide blocks 130, 131 guided for movement in engagement with the upper and lower portions of lever arms 124. The front ends of lever arms 124 are maintained in proper spaced relationship by a pivot shaft on which a clamping handle or locking lever 133, loosely positioned between the front ends of lever arms 124, is pivotally mounted. The upper end of a hook member 134 is pivotally mounted between the rearwardly facing flanges of locking lever 133, as at 135.

The upper end of hook member 134 normally overlies and is normally positioned forwardly of the vertical plane of shaft 132. Locking lever 133 extends rearwardly over and then downwardly past shaft 132 and has a hook portion 136 on the lowerend thereof which is adapted to engage the lower surface of a locking pin 137 suitably secured to and extending inwardly from the upper portion 36 of bearing block (FIGURES 1, 2 and 3). The composite pressure applying device (FIGURE 7) comprises elements 121, 122, 124'-126, 130'-137 which correspond to and may be identical to the respective elements 121, 122, 124126, 130-137 of FIGURE 3.

The flanged lower ends of those housings 120, associated with plungers 113, 114, 116, 117, 113,-114', 116, 117' are held. in engagement with the lower surfaces of the corresponding lower guide blocks 121, 130, 121, by internally threaded nuts 141, 142 (FIG- URE 3), 141', 142 (FIGURE 7) threaded onto the upper ends of corresponding tubular housings 120, 120' and engaging .the upper surfaces of corresponding upper guide blocks 122, 131, 122', 131, thus clampingly maintaining the housings 120, 120' in adjusted positions on the respective pairs'of lever arms 124, 124. The flanged lower ends of those housings 120, 120' associated with plungers 115, l15' may be held in engagement with the lower surfaces of the lower guide blocks 130, 130 by respective snap rings 143 (FIGURE 3) and 143 (FIG- URE 7) fixed in suitable peripheral grooves in the upper ends of the corresponding tubular housing 129, 120 and resting against the upper surfaces of the respective upper guide blocks 131, 131'.

Each plunger 113-117, 113-117 has an enlarged annular shoulder portion 145 thereon adapted to engage the upper surface of the restricted lower end of each corresponding tubular housing 120, 120 whenever the corresponding hook member 135 or 135 is released from engagement with the corresponding locking pin or 140. Thus, the lever arms 124 and 125, and the parts carried thereby, may be pivoted upwardly out of the way of an operator whenever it is desirable to remove the top rolls 16a, 17a and/or the top apron 40'a-nd its cradle 42 from the machine, for example.

Each housing 120, 120 has a compression spring 146 therein whose lower end engages the upper surface of the corresponding shoulder portion and whose upper end engages an externally threaded nut 147 (FIGURE 7) threaded into the upper end of the corresponding tubular housing. Preferably, the springs 146 associated with the plungers 115, 115 are smaller than the rest of the springs 146, since relatively lighter yieldable pressure is applied to the pivot pins 62, 62 of top apron cradle 42 than that applied to the corresponding elements by the remaining plungers 114, 116, 117,113, 114', 116, 117'.

The reduced upper portions of plungers 113-117, 113 117 are loosely encircled by the corresponding springs 146 and loosely penetrate and extend upwardly through the corresponding nuts 147 (FIGURE 7). and have corresponding graduations 150 thereon which may be arrangedto indicate the amount of pressure applied by the corresponding plungers when certain of the graduations are in alinement with the upper ends of the nuts 147.

In order to operate an electrical circuit to stop the machine or to provide some indication of the occurrence of winding of excessive fibers around any one or more of the drafting rolls 16, 16a, 17, 17a or around either of the aprons 40, 41, plungers 113, 114, 117, 115, 114, 117, extend upwardly a substantially greater distance above the corresponding housings 120, 120 or lever arms 124 and have respective contactors 152,152 threadedly or otherwise adjustably secured thereon which will close a circuit to an electrical stop motion or other electrically operable indicating device, not shown, when the corresponding plungers are raised excessively due to a lap-up and causes one or more of the contactors 152 or 152 to contact a corresponding metallic plate 153 or 153, as the case may be. Plates 153, 153' extend in parallel relation to the upper surfaces of the respective lever arms 124, 124', and downwardly projecting side flanges thereon are suitably insulatably secured to the outermost of the respective lever arms 124, 124.

From the foregoing description, it is apparent that as slivers S enter between the rear portions of the proximal runs of aprons 40, 41, they are subjected to a substantial relatively high pressure while the plungers 115, 115 (FIG- URES 3 and 7) apply a relatively light pressure to the fibers passing between the remaining portions of the proximal runs of aprons 40, 41, which pressure gradually diminishes as a given portion of the slivers S advances toward the front ends of the proximal runs of aprons 4t), 41. It is further apparent that control rollers 82, $3 apply alocalized squeezing action to the fibers therebetween to further contribute to the attenuation and straightening of the fibers as they are drawn or drafted by the front or delivery rolls 17, 17a. It should be noted that the pressure applied to the lower portions of the proximal runs of aprons 40, 41, to the cradle 42, and to the upper control roller 83 may be accurately predetermined in each instance.

It is also seen that the aprons 40, 41 may be maintained under optimum tension at all times and may be adjusted, unitarily, toward and away from the delivery rolls or feed rolls in accordance with the length of staple of fibers to be drafted. The adjustment of the aprons 40, 41 toward and away from the delivery rolls 17, 17a may be effected in structure heretofore described simply by loosening screws 25 and moving the bearing blocks 14, 14 (FIGURE 1) in the desired direction along the roll stands 11, 11 and then tightening the screws 25, 25. It is apparent that, whenever bearing blocks 14, 14 are adjusted longitudinally of the corresponding roll stands 11, 11, the rear apron-supporting rollers 18, 64, the shoe 46, the end blocks 50, 50', 6t 60, the front rollers 44, 65, the tensioning rollers 45, 55 and the aprons 40, 41 are moved unitarily therewith.

FIGURES 8 and 9 show another form of means for adjusting aprons 40, 41 toward and away from delivery rolls 16, 16a and/or feed rolls 17, 17a. Those parts shown in FIGURES 8 and 9 which are substantially identical to or correspond to like parts shown in FIGURES 17 shall bear the same reference characters, in order to avoid repetitive description, and only those parts peculiar to the embodiment shown in FIGURES 8 and 9 will be described. Although only one of the roll stands 11 and corresponding bearing blocks are shown in FIG- URES 8 and 9, it is to be understood that similar parts are provided at the opposite side of the machine or roll section.

It will be observed in FIGURE 8 that the lower portion of bearing block 14 is threadedly penetrated by a threaded front end portion of a shaft or screw which loosely penetrates the lower portion of the corresponding rear bearing block 13. Bearing block 13 also is threadedly penetrated by a threaded front end portion of a shaft 167 which extends rearwardly in substantially parallel relation with shaft 165. Shafts 165 extend rearwardly from bearing block 13 and are journaled in the lower portion of the corresponding post 126.

The rear ends of shafts 165, 167 extend outwardly beyond post 126 and have respective gears 170, 171 thereon which mesh with gears 172, 173 fixed on respective shafts 174, 175. Shafts 174, 175 extend laterally in substantially parallel relation to the axes of feed rolls 16, 16a, are journaled in suitable stationary brackets 176, and have hand control knobs 180, 181 fixed thereon which are so positioned as to be readily accessible to the operator. Bearing blocks 13, 14 are preferably mounted on roll stand 11 in FIGURES 8 and 9 by a dovetail connection 182, It is apparent that, by manipulating knobs 180, 181 to rotate shafts 174, 175, corresponding movement is imparted to bearing blocks 13, 14 for varying the distance between feed rolls 16, 16a and aprons 40, 41 and delivery rolls 17, 17a.

It is apparent that, whenever aprons 40, 41 are adjusted relative to roll stands 11, 11', control rollers 82, 83 remain in fixed positions with respect to roll stands 11, 11. However, the control rollers 82, 83 are adjustable independently of aprons 40, 41, unitarily, toward and away from delivery rolls 17, 17a in the manner heretofore described.

Although it is not absolutely necessary, the various bearings 26, 26', 27, 27', 67, 67', 91, 91, 85, 85' preferably include anti-friction bearing units such as needle bearings. Also, opposed ends of tension rollers 45, 55, 75 are preferably journaled on the corresponding stub shafts 45a, 45a, 55a, 55a, 75a, 75a by anti-friction bearings, and opposed ends of the relatively small front apron-supporting rollers 44, 65 are preferably journaled in the end blocks 50, 50, 60, 60' of cradles 43, 42, respectively, by means of anti-friction bearings.

In the drawings and specification there have been set forth preferred embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

Iclaim:

1. In combination with a drawing frame for doubling several textile slivers and having front and rear pairs of drafting rolls; a double apron drafting system including top and bottom endless aprons positioned between and spaced from said front and rear pairs of drafting rolls, front and rear spaced apron-supporting rollers for supporting each top and bottom apron and forming substantially parallel and juxtaposed proximal runs from said aprons between which said slivers pass from the front pair to the rear pair of drafting rolls, means applying a predetermined high yieldable downward pressure to the rear top-apron-supporting roller, and means for applying a predetermined relatively low yieldable downward pressure to the front top-apron-supporting roller substantially independently of the pressure applied to said rear top-apron-supporting roller.

2. A structure according to claim 1, including means for driving at least one of the bottom-apron-supporting rollers to drive the bottom apron in timed relation to the drafting rolls, and said top apron being driven solely by contact thereof with the bottom apron and the slivers passing between the aprons.

3. In combination with a drawing frame for doubling several textile slivers and having front and rear pairs of drafting rolls; a double apron drafting system including top and bottom endless aprons positioned between and spaced from said drafting rolls, top and bottom pairs of front and rear supporting rollers for supporting the respective top and bottom aprons and forming substantially parallel proximal runs from said aprons, a cradle including end plates in which said top-apron-supporting rollers are mounted, said end plates being pivotally mounted on said rear top-apron-supporting roller, means applying a predetermined yieldable downward pressure to said rear top-apron-supporting roller, and means applying predetermined yielda-ble downward pressure to a medial portion of said cradle forwardly of and adjacent said rear topapron-supporting roller.

4. A structure according to claim 3, including a topapron-tensioning member engaging the inner surface of said top apron along its width and remote from said proximal runs, said end plates having substantially vertically extending slots in their inner faces adjacent said top apron, stub shafts on which opposite ends of said tensioning mernbcr are journaled and having end portions fitting loosely in said slots, and a screw loosely penetrating the upper portion of each end plate, entering the corresponding slot and being threaded into the end portion of the corresponding shaft for adjusting said tensioning member toward and away from said proximal runs.

5. A structure according to claim 3, including a pair of upper and lower superposed control rollers spaced between said front and rear supporting rollers and between which said proximal runs are adapted to move in engagement therewith, means supporting one of said control rollers in a fixed position, and means applying a predetermined yielding pressure to the other of said control rollers toward said one control roller.

6. A structure according to claim 5, including means for adjusting said control rollers toward and away from said top and bottom rear apron-supporting rollers.

7. A structure according to claim 5, including a shoe having an upper surface engaging the lower surface of said bottom run and substantially spanning the distance between said rear bottom-apronsupporting roller and said lower control roller.

8. In a drawing frame for drafting masses of disoriented, loose, open textile fibers in the form of slivers, said frame having rear feed rolls and front delivery rolls; the combination of top and bottom endless aprons positioned between said feed rolls and said delivery rolls and having respective bottom and top juxtaposed runs between which slivers pass in their course from the feed rolls to the delivery rolls, means supporting and guiding said bottom apron adjacent opposite ends of said top run, means supporting and guiding said top apron adjacent op posite ends of said bottom run, means applying predeten mined yielding downward pressure to the top-apron-supporting means adjacent said feed rolls, a pair of upper and lower substantially vertically alined control rollers spaced from but located adjacent the front ends of said runs and engaging respective top and bottom surfaces of said top and bottom runs, and means applying a predetermined yielding downward pressure to said upper control roller independently of the means applying pressure to said top-apron-supporting and guiding means.

9. A structure according to claim 8, including means for adjusting said apron-supporting and guiding means, along with said aprons, toward and away from said delivery rolls.

10. A structure according to claim 8, including means for adjusting said control rollers relative to said apronsupporting and guiding means and toward and away from said delivery rolls.

11. A structure according to claim 8, including means for adjustably varying the pressure applied to said topapron-supporting and guiding means and said upper control roller independently of each other.

12. In combination with a drawing frame for doubling several textile slivers and having front and rear pairs of drafting rolls; top and bottom endless aprons positioned between and spaced from said drafting rolls, top and bottom apron-supporting rollers for supporting rear portions of the respective top and bottom aprons, top and bottom cradles each including end plates straddling the respective top and bottom aprons, a first pair of bearing blocks supported for forward and rearward adjustment on said drawing frame, straddling said cradles, and in which said top and bottom apron-supporting rollers are mounted, the end plates of said top cradle being pivotally mounted on said top-apron-supporting roller, top and bottom apron supporting members spaced forwardly from said rollers and extending between and being carried by the end plates of the respective top and bottom cradles and form ing substantially parallel and proximal runs'from said aprons, means maintaining said end plates of said bottom cradle in fixed relation to said pair of bearing blocks whereby forward and rearward adjustment of the bearing blocks effects corresponding unitary adjustment of said aprons, rollers and members, means applying a predetermined yieldable downward pressure to said top-apronsupporting roller, and means applying predetermined yieldable downward pressure to a medial portion of said top cradle forwardly of and adjacent said top-apron-supporting roller.

13. A structure according to claim 12, including means for tensioning said bottom apron comprising a pair of tension rollers straddling said bottom apron and spaced from said proximal runs below said bottom cradle, :21 pair of spaced tensioning blocks on which opposite ends of said tension rollers are mounted, means on said bearing blocks supporting said tensioning blocks for angular movement about a substantially horizontal axis whereby rotation of said tensioning blocks in one direction will increase the tension in said bottom apron, and means for releasably locking said tensioning blocks in adjusted position.

14. A structure according to claim 12, wherein said apron-supporting members are rollers journaled in the corresponding end plates.

15. A structure according to claim 12, wherein said bearing blocks are supported for forward and rearward adjustment on said drawing frame by means of dove-tail connections, means for adjusting said bearings comprising a substantially horizontal threaded shaft threaded into each bearing block and journaled and restrained from axial movement in a fixed part of said drawing frame whereby rotating said shafts adjustably varies the position of said bearing blocks. v

16. A structure according to claim 12, including a pair of upper and lower superposed control rollers above and beneath said proximal runs and spaced between said apron-supporting rollers and apron-supporting members, a separate bearing in which each end of each control roller is journaled, said end plates of said bottom cradle having surfaces supporting thereon the bearings in which opposite ends of said lower control roller are journaled, a second pair of bearing blocks supported for forward and rearward adjustment on said drawing frame and to which said last-named bearings are connected, said second bearing blocks having substantially vertically extending slots therein, and the distal ends of those bearings in which opposite ends of said upper control roller are journaled being mounted for vertical sliding movement in said slots whereby forward and rearward adjustment of said second pair of bearing blocks effects corresponding unitary adjustment to said control rollers relative to said aprons.

17. A structure according to claim 16, including means applying :a predetermined downward yieldable pressure to said upper control roller.

18. In combination with a drawing frame for doubling several textile slivers and having front and rear pairs of drafting rolls; a double apron drafting system including top and bottom endless aprons positioned between and spaced from said front and rear pairs of drafting rolls, rear, top and bottom, apron-supporting rollers for supporting rear portions of the respective top and bottom aprons, front, .top and bottom, apron-supporting members forming substantially parallel and juxtaposed proximal runs from said aprons between which aid slivers pass from the front pair to the rear pair of drafting rolls, means applying a predetermined high yieldable downward pressure to the top-apron-supporting roller, means for applying a predetermined relatively low yieldable downward pressure to the top-apron-supporting member substantially independently of the pressure applied to said top-apron-supporting roller, and means for unitarily adjusting said apron-supporting rollers and members, along with said aprons, toward and away from said front pair of drafting rolls.

19. In combination with a drawing frame for doubling several textile slivers and having front and rear pairs of drafting rolls; a double apron drafting system including top and bottom endless aprons positioned between and spaced from said front and rear pairs of drafting rolls, rear, top and bottom, apron-supporting rollers for supporting rear portions of the respective top and bottom aprons, front, top and bottom, apron-supporting members forming substantially parallel and juxtaposed proximal runs from said aprons between which said slivers pass from the front pair to the rear pair of drafting rolls, means applying a predetermined high yieldable downward pressure to the top-apron-supporting roller, means for applying a predetermined relatively low yieldable downward pressure to the top-apron-supporting member substantially independently of the pressure applied to said top-apron-supporting roller, a pair of upper and lower superposed control rollers between which said proximal runs are adapted to move in engagement therewith, means supporting one of said control rollers in a fixed position, means applying a predetermined yielding pressure to the other of said control rollers toward said one control roller, and means for adjusting said control rollers unitarily toward and away from said front pair of drafting rolls relative to said apron-supporting rollers and members.

References Cited by the Examiner UNITED STATES PATENTS 2,230,399 2/1941 Brandt et al 19244 X 2,319,367 5/1943 Schlurns 19256 X 2,955,330 10/1960 Kraft l9281 X 3,028,636 4/1962 Schiltknecht 19-250 FOREIGN PATENTS 583,586 10/1958 Italy. 359,074 1/1962 Switzerland.

OTHER REFERENCES Weller: German app. No. 1,118,072, pub. l123l96l.

ROBERT R. MACKEY, Primary Examiner.

MERVIN STEIN, Examiner.

P. C. FAW, Assistant Examiner. 

1. IN COMBINATION WITH A DRAWING FRAME FOR DOUBLING SEVERAL TEXTILE SLIVERS AND HAVING FRONT AND REAR PAIRS OF DRAFTING ROLLS; A DOUBLE APRON DRAFTING SYSTEM INCLUDING TOP AND BOTTOM ENDLESS APRONS POSITIONED BETWEEN AND SPACED FROM SAID FRONT AND REAR PAIRS OF DRAFTING ROLLS, FRONT AND REAR SPACED APRON-SUPPORTING ROLLERS FOR SUPPORTING EACH TOP AND BOTTOM APRON AND FORMING SUBSTANTIALLY PARALLEL AND JUXTAPOSED PROXIMAL RUNS FROM SAID APRONS BETWEEN WHICH SAID SLIVERS PASS FROM THE FRONT PAIR TO THE REAR PAIR OF DRAFTING ROLLS, MEANS APPLYING A PREDETERMINED HIGH YIELDABLE DOWNWARD PRESSURE TO THE REAR TOP-APRON-SUPPORTING ROLLER, AND MEANS FOR APPLYING A PREDETERMINED RELATIVELY LOW YIELDABLE DOWNWARD PRESSURE TO THE FRONT TOP-APRON-SUPPORTING ROLLER SUBSTANTIALLY INDEPENDENTLY OF THE PRESSURE APPLIED TO SAID REAR TOP-APRON-SUPPORTING ROLLER. 